Covenants; there's a lot of them about. Of Keys, of Lost Arks. Nobody knew about the one with Alien, but I think we all knew that it had been broken, certainly by the time it was being pitted against Predators, maybe before. The previous attempt to restore it failed. Some weeks before Prometheus came out I heard myself exiting the words, “If Ridley Scott can't make a decent Alien film, we may as well all pack up and go home.” Or, alternatively, stick it out and see what Prometheus 2 is like. The precedents for directors of films that spawned phenomenally successful sci-fi series, returning to make trilogies of prequels are not good, but this is definitely much more like it. The Union of the Snake is in declined, but the Covenant of the Alien is on its way back.

This isn't the Mother of all Alien films but it does all that could reasonably be expected of it – it delivers an entertaining Alien-riping-its-way-through-a-spaceship-crew narrative, while retrospectively making Prometheus seem worthwhile. Maybe they should have called it Prometheus: Validation, because to your great surprise, Covenant actually ties up most of the loose ends and themes of that film in a very satisfying way; to such a degree that you might almost believe that this had been their plan all along.

It starts with a scene possibly cut from the earlier film, between a younger Weyland (Guy Pearce) and his android creation David (Fassbender), just to let you know that all that stuff about finding our creators hasn't been forgotten. After that though it tries to put as much distance between that film and this as possible. While the spaceship Prometheus was bright and shiny and roomy, almost like an ocean liner with space for hidden luxury compartments that nobody knew about, the spaceship Covenant is dark and cramped, claustrophobic like a submarine. The crew are mostly American, rather than British, which I think we prefer (in David Fincher's Alien Cubed British audiences felt uneasy, almost a little cheated, with having locals like Brian Glover or Charles Dance in the cast.)

Covenant is a synthesis of Prometheus with traditional Alien films, and most of the novelty and interest is in the Prometheus strand. Here Scott gets to have fun doing the Alien equivalents of the Colonel Kurtz sequence in Apocalypse Now and revisiting the biblical plagues from his Exodus: Gods and Kings. The major redeeming factor of Prometheus was it featured one of Fassbender's very best screen performances and here he's just as impressive. There's a cheeky moment when he references a line used by Rutger Hauer in Blade Runner and it's a valid comparison. The life artificial burns very brightly in his films.

In the Alien strand, Waterston makes a really excellent Ripley surrogate, but the scares are surprisingly formulaic, mostly things you have seen before in Alien films, and the bits you haven't seen in other Aliens are taken from slasher films. (There's even a shower sequence, which just seems weird.) Scott's original Alien was a model of precision, while this one is a little bit messy, with too many characters that we don't get to know and you wish the visuals were a bit cleaner. My biggest issue with the film is how dark it is; if you were watching it on TV you'd be fiddling with the contrast button because you wanted to see more of what was going on.